Foster, D. W. (1972). Planning for products and markets. Longman.
Dyfyniad Arddull ChicagoFoster, Douglas W. Planning for Products and Markets. London: Longman, 1972.
Dyfyniad MLAFoster, Douglas W. Planning for Products and Markets. Longman, 1972.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.